We're dividing 42985909 by 399 
We want to divide 42985909 by 399.

Going ahead to step 1:
When dividing 4 by 399, we get 0 with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 399

Advancing to step 2:
When dividing 42 by 399, we get 0 with a remainder of 42.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 42, we get 42.
Bring next digit (9) of the dividend behind the 42 and repeat the process: 429 / 399

Going ahead to step 3:
If we divide 429 by 399, we get 1 and a remainder of 30.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we subtract 399 from 429, we get 30.
Grab the next digit (8) from the dividend, add it to 30, then carry on: 308 / 399

Going ahead to step 4:
If we divide 308 by 399, we get 0 and a remainder of 308.
Use 0 as the next digit of our solution. 
Result so far: 10.0
Deduct 0 from 308 and we're left with 308.
Append the next digit (5) from the dividend to 308 and continue with: 3085 / 399

Going ahead to step 5:
3085 divided by 399 is 7 with a remainder of 292.
Use 7 as the next digit of our solution. 
Result so far: 107.0
The remainder is 292 after subtracting 2793 from 3085.
Fetch the next digit (9) from the dividend, attach it to 292 and continue: 2929 / 399

Advancing to step 6:
399 can be fit into 2929 7 times, resulting in a remainder of 136.
Write down 7 as next digit of the result. 
Result so far: 1077.0
If we take 2793 away from 2929, we end up with 136.
Append the next digit (0) from the dividend to 136 and continue with: 1360 / 399

Advancing to step 7:
The number 399 fits into 1360 3 times, leaving a remainder of 163.
Put 3 as the next digit of the answer. 
Result so far: 10773.0
Subtracting 1197 from 1360 leaves us with 163.
Include the next digit (9) from the dividend after 163, then repeat: 1639 / 399

Let's proceed to step 8:
1639 divided by 399 is 4 with a remainder of 43.
Use 4 as the next digit of our solution. 
Result so far: 107734.0
If we take 1596 away from 1639, we end up with 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Moving on to step 9:
399 goes into 430 1 times with a remainder of 31.
The next digit of our result is 1. 
Result so far: 107734.1
Deduct 399 from 430 and we're left with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Let's proceed to step 10:
399 goes into 310 0 times with a remainder of 310.
Record the quotient 0 as the next digit in the result. 
Result so far: 107734.1
Subtract 0 from 310 to get 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3100, and continue the process.

On to step 11:
When dividing 3100 by 399, we get 7 with a remainder of 307.
Put 7 as the next digit of the answer. 
Result so far: 107734.107
Deduct 2793 from 3100 and we're left with 307.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3070, and continue the process.

On to step 12:
399 goes into 3070 7 times with a remainder of 277.
The number 7 becomes the next digit in our result. 
Result so far: 107734.1077
If we subtract 2793 from 3070, we get 277.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2770, and continue the process.

Our division results in 107734.1077 with a remaining 0.00277.